# -*- coding: utf-8 -*-

# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html

from scrapy import signals
import requests
import random

class ProxyMiddleware(object):
    """
    过滤全部ip中不能用的ip时
        1.首先可以使用一个简单网站先验证这个ip是不是有效的
        2.1有效的ip在请求具体网站的时候也会出现 不能使用的情况，这时过滤到刚开始就直接连接不上的ip
        2.2 到此时所有的ip都是可用的， 但是也会出现在使用的过程中某个ip的调用太过频繁而被封锁的情况， 也进行删除
        3.当ip列表的长度到达一个临界点时 进行重新获取新的ip列表
    """
    def __init__(self):

        self.ip_list = []

    def process_request(self, request, spider):

        while True:
            if len(self.ip_list) < 3:  # 设定代理ip的列表 小于某一个值时重新获取ip 并验证
                self.get_ip()
            else:
                break

        ip_raw = random.choice(self.ip_list)

        self.ip_list.remove(ip_raw)

        request.meta['download_timeout'] = 10
        print("本次使用的ip：", ip_raw)
        request.meta["proxy"] = ip_raw

    def get_ip(self):
                
        url = "http://pandora128.cn/fastapi/ipproxy/89ip"
        data={"num":10,"api":1}
        result=requests.post(url,params=data).json()["data"]

        for record in result:
            ip_one = ["http://{0}".format(record),"https://{0}".format(record)]
            self.ip_list.extend(ip_one)

    def process_response(self, request, response, spider):
        self.ip_list.append(request.meta["proxy"])

        print("代理池目前的大小为：", len(self.ip_list))
        return response


class ItorangeSpiderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, dict or Item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request, dict
        # or Item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class ItorangeDownloaderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)
